This invention relates in general to resilient supporting bearings and in particular to a new and useful support bearing having two fluid chambers particularly for the support of an engine in an autombobile.
The German Pat. No. 3,225,700 and the German Offenlegungsschrift 3,244,296 each describe two-chamber support bearings. For these known support bearings, an upper supporting member for attachment to the crankcase of the engine and a lower supporting member for attachment to a foundation, such as the body of a motor vehicle, are connected together by a spring element of rubber. The space below the spring element is provided with a partition which divides an upper chamber, acting as a working space, from a lower chamber, which assumes the function of an equalizing chamber, the walls are at least partly rubber-elastic in nature, so that the two chambers can change their volume. The partition has a connecting passage with a restrictor valve. In the construction of the German Pat. No. 3,225,700, this connecting passage is disposed ring-shaped in the partition. On the other hand, the German Offenlegungsschrift 3,244,296 has a straight, connecting passage between the upper chamber and the lower chamber. With this arrangement, a further, air-filled chamber is separated by a membrane for the purpose of a hydraulic decoupling of high frequencies in the upper chamber (working space). This membrane chamber is disposed centrally in the upper supporting member. This membrane also consists of rubber, the hardness of which, however, is different from that of the rubber-elastic wall of the lower chamber (equalizing space). In the event of oscillations of small amplitude, and exchange of fluid between the two chambers is largely prevented by the response of this membrane, so that an acoustic isolation of these oscillations is achieved.